Fluorine-containing elastomeric copolymers have high resistances to heat, oils and chemicals and have been employed for various uses, for example, gaskets, packings, diaphragms, hoses, etc. Due to such excellent properties, the copolymers also have great potential for use as electric insulating materials such as electric wire coating materials.
However, conventional fluorine-containing elastomeric copolymers have poor electric insulating characteristics or moldability and even the copolymers having good moldability are not satisfactory in mechanical strength or dielectric breakdown strength after thermal ageing. Thus, the fluorine-containing elastomeric copolymer compositions are not practically used sufficiently as electric insulating materials.